Card holders, and what RFID blocking is actually protecting you from

A slim wallet is a good idea that the internet has turned into a technology product. Twenty of them are on this page, fifteen of them lead with the same three letters, and the three letters are the least useful thing in the title.

What RFID blocking is, and what it is not

A contactless card carries a chip and an aerial. Hold it against a reader and it answers. The claim behind an RFID-blocking wallet is that a thief with a reader in a bag can walk past you and charge your card through your pocket.

It is worth being plain about how that works in practice. A contactless payment needs the card within a few centimetres of a reader, the reader has to belong to a merchant with a bank account the money goes to, and every transaction is logged against that merchant. The UK banking industry’s own fraud body has said for years that it has no verified case of a card being charged while still in its owner’s pocket. Contactless fraud exists, and it is done with stolen cards, not with readers in bags.

So the fifteen titles saying RFID are selling a lock for a door nobody has come through. That does not make the wallets bad. It makes the letters decoration, and there is a second thing worth knowing: a metal case blocks the signal whether or not the title says so, because that is what a metal box does. Eight of these are metal. The claim only means anything on a leather or PU wallet, where it means a foil layer sewn inside that you cannot see and cannot test.

Buy the wallet for the wallet.

Metal, leather or PU

Metal, on eight titles: aluminium, stainless steel, carbon fibre, or carbon fibre on aluminium. Hard, thin, and cards come out flat rather than fanned. Three of the eight are pop-up cases, with a lever on the side that slides the cards up in a fan. It is the one mechanism on this page that changes how a wallet is used, and it holds about six cards, all flat, no embossed old ones.

Leather, on five titles, four of which say genuine and one of those crazy horse. Genuine leather is a grade, and it is the bottom one: the split left after the top of the hide is taken, with a finish sprayed on. It is real leather and it is not the leather the word makes you picture. Crazy horse is a waxed full-grain finish, the kind that scuffs and darkens rather than peels, and it is the best leather word on the page.

PU, on four titles, is polyurethane on a fabric backing. It looks like leather for the first six months and then the edges go. At the price, that is a fair trade. It is only a bad one if you did not know.

The fifth says leather and nothing else. Assume PU. Three more titles say no material at all, and one of those calls itself a luxury brand.

What none of them says

How many cards. Not one title. A pop-up case takes six. A slim leather holder takes four comfortably and eight badly. A trifold takes more and is no longer slim. One title says large capacity, which is a word.

How thick. No millimetres anywhere, on a product whose whole point is thinness. Twenty-one titles say slim, thin or mini and none of them says what that is.

Whether cash fits. Four titles have a money clip or a cash strap. On the other sixteen, notes fold once and sit behind the cards, or do not.

The extras

An AirTag slot, on three titles. If you leave wallets in taxis, this is the one feature that helps, and the tag is not in the box. Two of the three are folding wallets; one is an aluminium case with a strap.

A coin pocket, on four. A coin pocket on a slim wallet is a small contradiction, and it is honest about who it is for: a country that still uses coins at the parking meter.

Magnetic, on one holder, means the flap closes on a magnet, and the strip on an older card does not love that. On a case where the cards are inside metal it is a non-issue.

Luxury brand, on one title, with no brand named. A brand is a name you can search. This is a description.

One row on this shelf is not a wallet at all but a phone case with card slots, and the MagSafe case guide covers what to check on those.

What I would actually do

For most pockets, the OUIO aluminium pop-up. A maker’s name, a mechanism that earns its place, and the coin pocket outside the case where it does not crease the cards.

For leather, the crazy horse money-clip wallet. It is the one leather word on this page that means the good kind, and a clip is how a slim wallet carries notes without getting fat.

For a person who loses wallets, the aluminium case with the AirTag slot and the cash strap. Buy the tag separately.

For a handbag, the leather card case in colours. It is sold for women as well as men, which on this shelf is rarer than it should be, and it is small enough to be the thing you pull out rather than the bag.

Whichever you choose, ignore the three letters, ask how many cards, and read the material twice.